1. Field of the Invention
The present invention relates to an adjustable spanner or similar gripping device of the type which comprises a shaft or a handle and a gripping head which is defined by two jaws, of which one is preferably stationary and the other is displaceable so as to permit variation of the opening or gap of the head, at least the second jaw being provided with cogs which are in permanent mesh with cogs rotatably journalled in relation to the shaft on a wheel which is actuable by, for instance, a spring to rotate in such a direction that the jaws always strive to approach one another, the wheel co-operating with a locking or arresting device which is switchable between two positions, namely a free position in which the wheel may rotate and a locked or arrested position in which rotation of the wheel is prevented and displacement of the one jaw in relation to the other is obstructed.
2. Description of the Related Art
Swedish patent specification No. 8401884-5, filed in the same name, discloses an adjustable spanner which utilizes a specific type of coupling entitled spline coupling for realizing mechanical interconnection. This prior art coupling fundamentally suffers from two major drawbacks, namely its relatively high cost and the fact that steplessness in interconnection is difficult to achieve, since the prior art coupling is stepped by its very nature, even if the steps may be made slight and, moreover, may be further reduced by specific additional measures. However, such measures in respect of the prior art coupling have a tendency to render the coupling even more expensive.